Xia Guoqi, Qu Cheng, Zhu Yunlong, Ye Jianjiang, Ye Kaiqi, Zhang Zuolun, Wang Yue
State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, P. R. China.
Angew Chem Int Ed Engl. 2021 Apr 19;60(17):9598-9603. doi: 10.1002/anie.202100423. Epub 2021 Mar 11.
Reported herein is a molecular design strategy of deep-blue emitters for resolving the lack of highly efficient deep-blue organic light-emitting diodes (OLEDs) featuring CIE (Commission Internationale de l'Eclairage) color coordinates matching the display requirements (<0.1). The strategy is to combine weak spiro-donor and spiro-acceptor groups into a linear donor-π-acceptor type of thermally-activated delayed fluorescence molecule through a sterically bulky π-spacer. The strategy endows an emitter with deep-blue emission, a narrower emission bandwidth (51 nm in toluene), a high photoluminescence quantum yield (0.95 in toluene), weak concentration quenching, and efficient triplet-exciton utilization, which are all attractive characteristics for emitters of deep-blue OLEDs with lower CIE coordinates. Owing to the rational design, the emitter has realized not only highly efficient doped deep-blue OLEDs with external quantum efficiencies (EQEs) up to 25.4 % and CIE less than 0.1 but also so far the most efficient nondoped deep-blue OLED (EQE up to 22.5 %) with CIE less than 0.1.
本文报道了一种用于解决缺乏高效深蓝色有机发光二极管（OLED）问题的深蓝色发光体分子设计策略，这些OLED的国际照明委员会（CIE）色坐标需符合显示要求（<0.1）。该策略是通过一个空间位阻较大的π-间隔基，将弱螺环供体和螺环受体基团组合成线性供体-π-受体型热激活延迟荧光分子。该策略赋予发光体深蓝色发射、更窄的发射带宽（甲苯中为51 nm）、高光致发光量子产率（甲苯中为0.95）、弱浓度猝灭以及高效的三线态激子利用效率，这些都是具有更低CIE坐标的深蓝色OLED发光体的诱人特性。由于设计合理，该发光体不仅实现了外量子效率（EQE）高达25.4%且CIE小于0.1的高效掺杂深蓝色OLED，还实现了目前CIE小于0.1的最高效非掺杂深蓝色OLED（EQE高达22.5%）。
